On the backdrop of the "put options" and "call options" - two common contracts in the practice of the capital markets - lies this comparative law analysis concerning the approach taken by three jurisdictions to the concept of the unilateral promise.The outcome of the discussion is a criticism toward the English jurisdiction where this concept is missing, the same being replaced, in a non-convincing way, by the similar concept of the "unilateral contract". In addition to this, the requisite of the consideration, peculiarly requested in that jurisdiction, could even result in putting at risk, in some circumstances, the same validity and enforceability of these typologies of transactions.As to the Scottish jurisdiction, stranded between its ancient Roman roots and its "British ties", the work seeks to demonstrate that, although the "unilateral promise" is accepted in this jurisdiction (these making both "put options" and "call options" theoretically safe under this jurisdiction), there is still a non-perspicuous categorization of the concept and, particularly, a possible "blunder" in the way this jurisprudence seems to put together, in a sort of conceptual "melting pot", both the promise to the public (in incertam personam) and that aimed at the conclusion of the contract. However, this possible erroneous view - quite transparent in the light of the civilian jurisdiction adopted as comparator (the Italian one) - could find a potential "way-out", should the Scots legal system eventually adopt a code in the matter of the contracts more in line with its traditions and peculiarities.On the backdrop of the "put options" and "call options" - two common contracts in the practice of the capital markets - lies this comparative law analysis concerning the approach taken by three jurisdictions to the concept of the unilateral promise.The outcome of the discussion is a criticism toward the English jurisdiction where this concept is missing, the same being replaced, in a non-convincing way, by the similar concept of the "unilateral contract". In addition to this, the requisite of the consideration, peculiarly requested in that jurisdiction, could even result in putting at risk, in some circumstances, the same validity and enforceability of these typologies of transactions.As to the Scottish jurisdiction, stranded between its ancient Roman roots and its "British ties", the work seeks to demonstrate that, although the "unilateral promise" is accepted in this jurisdiction (these making both "put options" and "call options" theoretically safe under this jurisdiction), there is still a non-perspicuous categorization of the concept and, particularly, a possible "blunder" in the way this jurisprudence seems to put together, in a sort of conceptual "melting pot", both the promise to the public (in incertam personam) and that aimed at the conclusion of the contract. However, this possible erroneous view - quite transparent in the light of the civilian jurisdiction adopted as comparator (the Italian one) - could find a potential "way-out", should the Scots legal system eventually adopt a code in the matter of the contracts more in line with its traditions and peculiarities.